"On the PCSTATS test bench today is a unique 2nd Gen. Solid State Hybrid Drive (SSHD) from Seagate called the Momentus XT. This hybrid drive doesn't run on Hydrogen, but rather combines 8GB of SSD-grade SLC NAND flash with a standard 750GB two-platter 7200RPM notebook HDD. Looking no different than any common 2.5" notebook hard drive, the trick up the Momentus XT's sleeve that it learns what data you frequently use and caches this to its 8GB of internal flash memory."